System of distribution



J. F. PETERS SYSTEM 01? DISTRIBUTION Nov. 15,1927.

Filed May 24, 1923 J XXXXXJA WITNESSES:

ATTORN EY Patented Nov. 15, 1927.

UNITED STATES PATENT OFFICE.

JOHN F. PETERS, OF EDGEW DOD PARK, EENNSYLVAHIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC MANUFACTURIEG VANIA.

COMPANY, A. CORPORATION OF PENNSYL- sYsrnM or nisraiizurion.

Application filed May 24,-,

My invention relates to alternating-current systems of distributionand ithas particular relation to constant-current systems employed for series lighting and the like.

More particularly, my invention relates to systems in which current of constant value is derived through a plurality of reactive devices connected alternately in circuit with a source of constant potential.

The object ofmy invention is to provide means for .protecting the system from ex.- -cessive voltage strains occasioned by accidental interruption of the constant-current circuit. i i g It is known that when four elements offering equal reactances to currents of the same frequency, two of said elements being condensive and two being inductive, are so connected in a closed circuit as to alternate in position withone another, and an alternating-current voltage of constant value and the proper frequency is impressed across two opposite points of the'closed circuit, current of constant value may be obtained in a single circuit that is connected across the other two opposite points of the closed circuit. This arrangement of reactance elements, in which the current flowing in the constant-current receiving circuit is maintained under certain conditions 90 out of phase relation with the constant voltage impressed by the constant-potential supply circuit has been termed a monocyclic square.

hen a series lighting circuit is di rectly connected to this source of constant current, dangerous voltage conditions may result if the lighting circuit is accidentally interrupted. To overcome this difiiculty, I propose to interpose a transforming device of such character as to suitably limit the voltage rise upon the occurrence of said open circuit.

My invention will be best understood by reference to the accompanying drawing, in which Figure 1 is a diagrammatic view of cir cuits and apparatus embodying my invention.

Fig. 2 represents, diagrammatically, a modification of the system of Fig. 1, and

Fig. 3 is a plan view representing a convenient arrangement of circuits and apparatus embodied in my invention.

Referring to Fig. 1, a series lighting cir- 1923. Serial No. 641,072.

cuit comprising a plurality of lamps 1 is connected, by means of conductors 2 and 3,

to opposite points of a closed circuit or.

the constant current derived from circuit 4 is supplied to conductors 2 and 3 through a protective device comprising an autotransformer 11, provided with taps to take care of variations in supply voltage.

In Fig. 2 I have employed, in lieu of the auto-transformer 11, a single-phase distributing transformer 21 of a familiar type. In either case, the transformer is provided with an iron core that is worked at fairly high flux density under normal operating conditions. Any other suitable reactance device may be employed having this necessary saturation feature.

When constant-potential energy is supplied to conductors 9 and 10, current of constant value is derived and traverse conductors 2 and 3 of the series lighting circuit. Upon the accidental interruption of the latter circuit, the derived or secondary voltage will increase only su'liiciently to make the magnetizing current of the transformer 11 or 21 equal to the normal line current. On account of the saturation characteristic of the transformer, I have been able to limit this voltage to approximately 50% in excess of normal line voltage that is impressed upon the reactance elements 5, 6, 7, and 8. VVithout this arrangement, that is, when the transformer 11 or 21, is omitted and conductors 2 and 3 are connected directly to the opposite corners of the circuit 4, it is found that the voltage occasioned upon the interruption of the lighting circuit is sufficiently high to damage the reactance devices or injure the insulation of the various conductors, since there is then no provision for absorbing this voltage.

In Fig. 3, I have illustrated a convenient outdoor arrangement for mounting the re quired apparatus, which includes oil tanks 12 and 13 containing the reactive elements 5, 6, 7 and 8 and mounted, as transformer tanks are customarily mounted, upon cross arms 14 and 15 supported by a pole 16.

The simplicity and elliciency of my invention Will be apparent from the foregoing de scription and the invention should find ready application for the reasons set forth. I find preferable the arrangement of Fig. 1 in which taps are provided to talre care of variations in supply voltage. Also, I lind that the monocyclic square maybe constructed for its maxiuuun economy, that is, as best suited for the reqi'iirements of any particular installation, and all necessary provisions to procure current of proper value for the lighting circuit are obtainable by the suitable adjustment of the auto-trans former. I avoid the use of a u'iovingcoil type of transformer and provide apparatus better adapted to out-of-door installations.

Various modifications of my invention may be made by those skilled in the art Without departing from the spirit and scope of my invention and I desire, therefore, to be limited only in accordance With the appended claims.

I claim as my invention:

1. In a system of distriluition, the combination with a monocyclic square for converting constant potential to constant cur rent, of means comprising a substantially saturated transformer connected to certain corners of said square and receiving constant current therefrom for inherently determining the maximum potential upon said square when the constant current circuit is interrupted.

2. The combination With a. source of alternating current of constant potential and a load circuit, of a plurality of reactive devices connected alternately in circuit with said source and arranged in a closed circuit to supply the load circuit with current of constant value, a substantially satu rated transformer connected to points of opposite polarity in said closed circuit, and

energy-consuming means comprising said load circuit connected to said transformer, said transformer functioning to limit to a predetermined value the voltage strain occasioned by the interruption of said load circuit.

3. A current-transforming network com prising eapacitative and inductive reactance devices so assembled as to transform constantpotential alternating-current energy to substantially constant-current alternatingcurrent energy, said network having constunt-potential terminals and constant-cur rent terminals, an iron-core transformer having primary terminals and secondary terminals, said primary terminals being connected across the constant-cLu-rent terminals of said network, said transformer being sub stantially sati'irated When normal load conditions exist at the secondary terminals thereof and being capable of receiving, as magnetizing current, the full constant-current output of said network for inherently determining the maximum potentials obtained when the secondary circuit of the transformer is open-circuited.

4. An alternating-current s 'stem comprising a variable load circuit requiring substantially constant currents as variable voltages, a substantially constant-current source adapted to supply substantially constant currents at variable voltages, said source being of such nature as to develop dangerously high voltages if open-circuited and an ironcore transformer connected between said source and said load circuit, said transfm'mer operating near saturation under normal load conditions and being capable of receiving, as magnetizing current, the full constantcurrent output of said source for inherently determining the maximum potentials obtained when the load circuit is open-circuited.

In testimony whereof, I have hereunto subscribed my name this ltth day of May,

JOHN F. PETERS. 

